Lineswitch equipment



Patented Aug. 16, 1932 UNITED S'S'T-A'ATES PATENT OFFICE GEORGE E. STONEBRIDGE, on NEW YORK, N. Y., Ass GNoaB MESNE ASSIGNMENTS, TO

ASSOCIATED ELECTRIC LABORATORIES,

TIONIOF DELAWARE INC., OF CHICAGO, ILLINOIS, A CORPORA- LINEsWIToH EQUIPMENT Application filed January 1930. Serial No. 420,348.

'15 occur when calls are simultaneously .ini-

tiated on lines in the same group, and also when one or more calls accumulate during the operation of the master switch. It may be noted that when the master switch is in "80 motion battery is disconnected from the pulldown magnets of all lineswitches of the group, thereby preventing the switches from operating if calls come in at this time. However, in case two or more calls are waiting when the master switch operationceases and battery is reconnected to the pull-down magnets, the associated lineswitches will plunge in on the same trunk. Such connections are prevented in this present invention by making it possible for only one pull-down magnet circuit to be completed'at any one time.

Referring now to the drawing, there is shown a substation A with a line terminating in lineswitchLS, which is one of a group of lineswitches controlled by the master switch MS. The group may comprise twenty-five, fifty, seventy-five or one-hundred lineswitches, groups of this size being most commonly used. Associated with each master switch is one or more distributor switches D 'throughwhich operating ground is fed to the pull-down magnets of the lineswitches. The distributor switch; shown is of the twenty-five point, non-homing,.rotary type, although obviously switches ofany convenient capacity may be used. In the case of the twenty-five point switch, one or more switches will be required, depending on the size of the group controlled by the master I switch. In case a distributor switch of larger capacity is available, one switch may care for the entire group of lines, although in the larger groups this arrangement has a tend ency to slightly delay the extension of calls during the'busy period. With either arra-ngement the possibility of double connection is either entirely eliminated or reduced to a neglible quantity.

To better illustrate the function and utility of the invention the operation of the apparatus involved will now be described in detail. When the receiver is lifted at substation A, a circuit is closed for the line relay 1 of lineswitch LS, which may be traced from battery, winding of relay 1, normally closed contacts 6, line conduotor20, through the loop at the calling substation A, line conductor 19, normally closed contacts 7, common conductor 22, through the winding of relay 3 of the distributor switch D to ground. It will be assumed first that no other lines in the group are calling at this time, and that wiper 30 of the distributor switch stands in the position shown. Relay 1 energizes over the above traced circuit in series with relay 3 which also energizes. Relay 3 connects ground to the common signalling lead at contacts 26, and at contacts 25 closed a circuit from ground, contacts 25, contacts 28, interrupter contacts 29, winding of motor magnet 5, over the common conductor 24:, to open main battery at themaster switch MS. Magnet 5 energizes over this circuit and opens its own circuit at interrupter contacts 29. The magnet on releasing advances the wiper 30 one step, and again closes its own circuit 'at interrupter contacts 29. This cycle of operation is repeated and wiper 30 is advanced a step at a time until contact 31 is encoun- W tered, at whichtime a circuit is closed from ground through the winding of relay 4,

.wiper 30, contact 31, conductor 23, operated contacts 32 of relay 1, through the lower or pull-down windingof the pull-down magnet 2, to open main battery'by way of common conductor 24. Relay 4 operates over the above traced circuit and at contacts 28 opens the stepping circuit so that wiper 30 remains in engagement with contact 31. Relay 4 then shunts its own winding by connecting ground an interval after the contacts 27 areclosed.

When the plunger is forced into the banks, the springs 10, 11, and 12 are forced into engagement with contacts 13, 14, and 15,.respectively, and the calling line loop is extendedover trunk conductors 16 and 18. Release trunk conductor 21 is extended over trunk conductor 17. The trunk comprising conductors 16-18 incidently may terminate in an automatic switch or may extend to an operators position, in either case the terminating apparatus will be so arranged that when the loop is extended thereto, a holding ground will be returned on conductor 17. The holding winding of magnet 2 will energize from this ground on the release trunk conductor and maintain the: plunger of the switch in operated position. Relays 1 and 4 will restore after the necessary delay, and the distributor switch will be available for the next call.

It will be noted that a branch of conductor 17 is extended to the master switch MS. This is in accordance with the usual practice of operating a master switch from ground returned over the release trunk conductor. The master switch operates in. the well known way to realign the plungers of the other line switches opposite the next idle trunk in the group, at the sametime disconnectingfthe open main battery from common conductor 24. to

prevent'the operation of any pull-down mag.- net, corresponding to magnet 2, or the motor magnet 5 of the distributor switch D and other distributor switches when used, at this time. This arrangement substantially prevents double connections when calls accumulate in. different groups duringthe master switch operation since thevarious distributor switches do not start to hunt until the master switch finds an idle trunk.

Conductor 22 leading'from relay 3 is'eommon to all lineswitches of the group served by the distributor D. In the event that calls originate on other lines of the group during the operation just described, the relay 3 will be held energized in series with the line relays of the calling lineswitches and will maintain the signalling and stepping circuits previously described. This is without effect, however, until the lineswitch LS-is completely operated and the relay 4 deenergized. Relay 4 on restoring again completes the step ping circuit for magnet 5, and wiper 30 will be advanced asin the previous instance, until the contact, corresponding to contact 31, of

Immediately below the distributor switch D is shown the starting relay 3 of another distributor switch which corresponds in all respects to theswitch D but serves as group of lines. switch is required only when the line cups are of suchv size that it is not convenient to serve them with a single distributor switch asv shown. Any number of these switches may be provided for a group and. will function in exactly the same manner as described for the switch D. The signal common which wasshown multipled to the front contacts of the relay 3 and 3-" will take the place of the ordinary supervisory ground signal lead commonly used with plunger lineswitches. This signal lead will extend toa delay device, and in case any of the relays3 are held operated for an unusual length. of time, will; operate its signal device tocall attention to the condition obtaining.

Having described the invention, what is thought new and is desired to have protected by Letters Patent will be set forthv in the appended claims.

What is claimed is 1. In combination, a plurality ofsubscrihers individual line switches, an operating magnet for each switch, a normally open cit-- cuit for each magnet, and a distributor switch for completing said circuits one at a time.

2.. In a combination, a plurality of automatic switches, an operating magnet for each switch, a distributor switch operable under control of any of said automatic switches, contacts accessible to said distributor switch, a circuit for each operating magnet including a separate one of said contacts, and means responsive toany one of said switches-being taken into use for operating said distributor switch to connect with the contact associated with said oneswitch.

In combination, a plurality of plunger type lincswitches each having a line relay and a pull-down magnet, a master switch. for positioning the lineswitches before idle trunk lines, a distributor switch, and a circuit for the magnet of each lineswitch controlled 7 arate This additional distributor jointly by the associated line relay and said distributor switch.

4. In a telephone system, a'plurality of non-numerical switches presided over by a common master switch and having access to a plurality of trunk lines, means for operating any switch to connect with an idle trunk line, and a distributor switch for preventing the operation of more than one of said switches at a time.

5. In a telephone system, a plurality o non-numerical switches presided over by a common master switch and having access to a plurality of trunk lines, means responsive to the seizure of one of said non-numerical switches for operating the switch to seize an idle trunk line, and a distributor switch for controlling the operation of said non-numerical switches to prevent the simultaneous seizure of the same trunk line by two non-numerical switches.

6. In a. telephone system, a plurality of non-numerical switches presided over by a common master switch and having access to a plurality of trunk lines, a distributor switch having access to said non-numerical switches, means responsive to the seizure of one of said non-numerical switches for operating said distributor to hunt for and connect with the seized non-numerical switch, and means controlled by said distributor for operating the seized switch to connect with an idle trunk line.

7. In a telephone system, a plurality of non-numerical switches presided over by a common master switch and having access to a plurality of trunk lines, means for seizing said switches, a distributor switch for merical switches, and means responsive to the seizing of a plurality of said non-numerical switches for causing said distributor switch to operate the seized switches one at a time, whereby, each switch connects with a different trunk line.

8. In a telephone system, a plurality of non-numerical switches each having a line relay and an operating magnet, a distributing device, contacts individual to said nonnumerical switches accessible to said device, means for operating the line relay on one of said switches, means responsive to the operation of said line relay for causing said device to engage the contact associated with said one switch, and means responsive to the device engaging said contact for operating the magnet of said one switch.

9. In a telephone system, a plurality of non-numerical switches each having a line relay and an operating magnet, a switching device, a starting relay for said device, contacts individual to said switches accessible to said device, means for operating the line relay of any switch and said starting'relay in series responsive to the seizure of a switch,

means responsive to the operation of said starting relay, for operating the device into engagement with the contact associated with the seized switch, and means controlled jointly by the line relay of the seized switch and said device for operating the magnet of the seized switch. 1 a

10. In a telephone system, a subscribers' of the switch with which it has connected,

11.. In a telephone system, a group of automatic switches, an operating magnet for each switch, a relay for each switch operated responsive to the switch being taken into use to prepare acircuit for the associated mag net, and a distributor switch for completing the prepared circuits successively. I

12. In a telephone system, a group of automatic switches having common access to a plurality of trunk lines, amagnet for each switch for. efiecting a connection with any one of said trunk lines, a relay for each switch operated responsive tothe switch being taken into use to prepare a circuit for the associated magnet, and a distributor switch for completing the prepared circuits successively whereby each of the switches .connects with a different trunk line. controlling the operation of said non-nu- V 13. In a telephone system, a group of auto matic switches having common access to a group of trunklines, means responsive to a switch being taken into use for causing the switch to connect with an idle one of said trunk lines, and a distributor switch for preventing more than one switch at a time from operating to connect with a trunk line when a plurality of switches are taken into use simultaneously.

14. The combination comprising a plurality of non-numerical switches having access to a group of trunk lines, a common control switch for positioning said switches in selective relation with an idle one of said-trunk lines, and a second common control switch for completing the operating circuits for said first switches successively.

15. The combination comprising a plurality of plunger type lineswitches having common access to a group of trunk lines, a master switch for positioning the lineswitches before an idle one of said trunk lines, a relay for each lineswitch operated responsive to the switch being taken into use, a magnet for each lineswitch for efiecting a connection with a trunk line, a distributor switch common to said 'lineswitches, and an operating circuit for the magnet of each lineswitch con trolled jointly by the associated line relay, said master switch andsaid distributor switch. 7 Y i I 16. The combination comprising a plurality of non-numerical switches presided over by a common master switch for positioning the switches before'idle trunk lines accessible thereto, of a distributor switch for preventing the simultaneous'operation of two or more of said switches, and circuit connections for preventing the operation of any of said lineswitches or said distributor switch While said master switch is in operation.

17 In a telephone system, a group of nonnumerical switches each equipped with an operating magnet, a distributor switch including a wiper adapted to engage contacts :29 individual to each ofsaid first switches,'means responsive to any one of said first switches being taken into use for. operating the distributor switch to advance said wiper stepby-step over said contacts, and means responsive to said wiper engaging the contact individual totheswitch in use for operating the magnet ofthat switch.

' 18-. In a telephone system, a group of nonnumeri'eal switches each equipped with an operating magnet, a distributor switch including a Wiper adapted to engage contacts individual to'eaeh of said first switches, a circuit completed responsive to any one of said first switches being'taken into use for operating the distributor switch to advance said wiper step-by-step over said contacts, and means responsive to said wiper engaging the contact individualto the switch intuse for operating the magnet of that switch and for opening said circuit.

In witness whereof, I hereunto subscribe my name this 6th day of January, A. D. 1930.

- GEORGE E. STONEBRIDGE. 

